using System;

public class Program

{

    public static void Main()

    {

        double i;

        double product10 = 1, product20 = 1, product50 = 1, product100 = 1, product1000 = 1;

        for (i=1; i<11; i++) 

        {

            product10 *= i;     

        }

        for (i=1; i<21; i++) 

        {

            product20 *= i;     

        }

        for (i=1; i<51; i++) 

        {

            product50 *= i;     

        }

        for (i=1; i<101; i++) 

        {

            product100 *= i;        

        }

        for (i=1; i<1001; i++) 

        {

            product1000 *= i;       

        }

        Console.WriteLine("the product of the first 10 numbers is " +product10);

        Console.WriteLine("the product of the first 20 numbers is " +product20);

        Console.WriteLine("the product of the first 50 numbers is " +product50);

        Console.WriteLine("the product of the first 100 numbers is " +product100);

        Console.WriteLine("the product of the first 1000 numbers is " +product1000);

    }

}